Goodreads

Goodreads.com is the world’s largest site for readers and book recommendations, launched in 2007. Find out if a book is a good fit for you from user reviews, check series order and discover similar books and authors you may enjoy.
Sign up for a free member account and track the books you're reading, have read, and want to read. Use the handy smart phone app to scan books directly into your account for future reference. Invite your friends to your account to see which books your friends are reading.